Unless otherwise indicated herein, the description provided in this section is not prior art to the claims and is not admitted to be prior art by inclusion in this section.
Various types of hearing prostheses provide people having different types of hearing loss with the ability to perceive sound. Hearing loss may be conductive, sensorineural, or some combination of both conductive and sensorineural. Conductive hearing loss typically results from a dysfunction in any of the mechanisms that ordinarily conduct sound waves through the outer ear, the eardrum, or the bones of the middle ear. Sensorineural hearing loss typically results from a dysfunction in the inner ear, including the cochlea where sound vibrations are converted into neural signals, or any other part of the ear, auditory nerve, or brain that may process the neural signals.
People with some forms of conductive hearing loss may benefit from hearing devices such as hearing aids or electromechanical hearing devices. A hearing aid, for instance, typically includes at least one small microphone to receive sound, an amplifier to amplify certain portions of the detected sound, and a small speaker to transmit the amplified sounds into the person's ear. An electromechanical hearing device, on the other hand, typically includes at least one small microphone to receive sound and a mechanism that delivers a mechanical force to a bone (e.g., the recipient's skull, or middle-ear bone such as the stapes) or to a prosthetic (e.g., a prosthetic stapes implanted in the recipient's middle ear), thereby causing vibrations in cochlear fluid.
Further, people with certain forms of sensorineural hearing loss may benefit from hearing prostheses such as cochlear implants and/or auditory brainstem implants. Cochlear implant systems, for example, make use of at least one microphone (e.g., in an external unit or in an implanted unit) to receive sound and have a unit to convert the sound to a series of electrical stimulation signals, and an array of electrodes to deliver the stimulation signals to the implant recipient's cochlea so as to help the recipient perceive sound. Auditory brainstem implant systems use technology similar to cochlear implant systems, but instead of applying electrical stimulation to a person's cochlea, they apply electrical stimulation directly to a person's brain stem, bypassing the cochlea altogether, still helping the recipient perceive sound.
In addition, some people may benefit from hearing prostheses that combine one or more characteristics of the acoustic hearing aids, vibration-based hearing devices, cochlear implants, and auditory brainstem implants to enable the person to perceive sound.